Abstract
The aim of this study is to assess differences in patient characteristics,
tumour characteristics and hormone levels between acromegalic patients with
and without hyperprolactinemia. 44 patients of the University Hospital of
Brussels, Belgium with acromegaly who were diagnosed between January 2007
and July 2018 were included in this study. Nineteen patients were classified
in the hyperprolactinemia group and 25 patients were classified in the
normoprolactinemia group. No significant differences between acromegalic
patients with and without hyperprolactinemia were found in age at diagnosis,
gender, presence of hyperprolactinemia symptoms, insulin-like growth factor
1, growth hormone and testosterone levels, tumour volume, tumour
invasiveness, immunohistochemistry of growth hormone and prolactin, Ki-67
index and mitotic index. However, for a cut-off of 10% of
prolactin-positive cells, there was a trend towards a higher percentage of
prolactin-positive tumours in hyperprolactinemia patients (p=0.054)
and higher mean prolactin level in case of positive prolactin immunostaining
(p=0.007)). In our study there were no differences in
characteristics between acromegaly patients with hyper- and
normoprolactinemia. An association between the serum prolactin level and the
positivity of prolactin immunohistochemistry of the adenoma tissue was
found. The absence of a difference in tumour volume between patients with
hyper- and normoprolactinemia suggests that the hyperprolactinemia is likely
to be caused by the co-secretion of growth hormone and prolactin by the
tumour. Finally, for the first time, the cut-off of 10% of prolactin
cells was validated for the diagnosis of somatolactotroph tumours in
acromegaly.
Key words
anterior pituitary - prolactin - GH-Prl adenoma - pituitary tumour - somatolactotroph tumour
